U.S. patent application number 10/400662 was filed with the patent office on 2003-10-02 for hose clamping structure.
This patent application is currently assigned to TOKAI RUBBER INDUSTRIES, LTD.. Invention is credited to Nishimura, Motohide, Yuzuriha, Chiaki.
Application Number | 20030184087 10/400662 |
Document ID | / |
Family ID | 28449715 |
Filed Date | 2003-10-02 |
United States Patent
Application |
20030184087 |
Kind Code |
A1 |
Nishimura, Motohide ; et
al. |
October 2, 2003 |
Hose clamping structure
Abstract
A hose clamping structure 10 includes: a metal pipe 11 having an
inserting end portion 12 straightly extending in an axial direction
at one end and having a ring-shaped projecting portion 13 at a
leading end of the inserting end portion 12; a rubber hose 16
insertedly fitted to the entire outer surface of the inserting end
portion by press-fitting and secured thereto in an unbonded manner;
and a tubular sleeve member 21 mounted to the outer surface of the
rubber hose and extending over the substantially full length of the
inserting end portion, and tightened from outside so as to clamp
the rubber hose. The sleeve member includes a second tightening
portion 27 and a first tightening portion 24 apart from each other
in an axial direction. The first tightening portion includes a
tubular portion 25 substantially parallel with the axial direction
at the side of the second tightening portion, and a tapered portion
26 tapered and widened into a conical shape from the tubular
portion toward the leading end of the inserting end portion.
Inventors: |
Nishimura, Motohide;
(Kani-shi, JP) ; Yuzuriha, Chiaki; (Kasugai-shi,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TOKAI RUBBER INDUSTRIES,
LTD.
Komaki-shi
JP
|
Family ID: |
28449715 |
Appl. No.: |
10/400662 |
Filed: |
March 28, 2003 |
Current U.S.
Class: |
285/256 |
Current CPC
Class: |
F16L 33/2073
20130101 |
Class at
Publication: |
285/256 |
International
Class: |
F16L 033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2002 |
JP |
2002-095269 |
Claims
What is claimed is:
1. A hose clamping structure comprising: a metal pipe having an
inserting end portion straightly extending in an axial direction at
one end and having a ring-shaped projecting portion at a leading
end of the inserting end portion; a rubber hose insertedly fitted
to the entire outer surface of the inserting end portion of said
metal pipe by press-fitting and secured thereto in an unbonded
manner; and a metallic tubular sleeve member mounted to the outer
surface of said rubber hose and extending over the substantially
full length of said inserting end portion, and tightened from
outside toward an axial center direction along a circumferential
direction so as to clamp said rubber hose to said metal pipe,
wherein said sleeve member is tightened in a two-stage tightening
operation where the sleeve member is tightened at two portions
apart from each other in an axial direction, and a first tightening
portion at the leading end side of said inserting end portion is
longer in length than a second tightening portion inwardly located
in an axial direction, and said first tightening portion extends to
reach the leading end of said inserting end portion.
2. A hose clamping structure according to claim 1, wherein said
first tightening portion is formed by an integral unit including a
tubular portion substantially parallel to an axial direction at an
inner end side in an axial direction, and a tapered portion tapered
and widened into a conical shape from said tubular portion toward
the leading end of said inserting end portion.
3. A hose clamping structure according to claim 1 or 2, wherein the
tightening rate of said tapered portion when it compresses said
rubber hose between said tapered portion and said ring-shaped
projecting portion is 30 to 40 percent.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a hose clamping structure
in which a hose insertedly fitted to the outer surface of an
inserting end portion of a metal pipe is clamped and secured to the
metal pipe by tightening a sleeve member which is provided to cover
the outer surface of the hose.
[0002] Conventionally, hose clamping structures of this type are
classified into those for fuel hose having relatively low
pressure-resistance (10 kgf/cm.sup.2) and those for power steering
hose or freon hose having high pressure-resistance (100
kgf/cm.sup.2). In one exemplary hose clamping structure for a fuel
hose, an adhesive agent is applied over the outer surface of a
metal pipe; the resultant metal pipe and a rubber hose are adhered
to each other; and a sleeve member mounted to the outer surface of
the hose is tightened to a rubber hose in a flat tightening
operation where the tightening section is tightened over a wide
area substantially parallel to the axial direction. In another
exemplary hose clamping structure for a fuel hose, an elastic
member is interposed between a metal pipe and a rubber hose; for
example, an elastic coating agent such as a rubber paste and the
like is applied to the metal pipe; and a sleeve member is tightened
onto a rubber hose at two portions in an axial direction in a
two-stage tightening operation. In the case of a hose clamping
structure for a power steering hose, ring-shaped grooves are formed
in advance by a rolling process and the like at three portions of
an inserting end portion of a metal pipe in an axial direction; a
rubber hose is insertedly fitted to the metal pipe; a sleeve member
is provided to cover the hose; and the sleeve member is tightened
onto the rubber hose in a three-stage tightening operation at
positions corresponding to the ring-shaped grooves of the metal
pipe. As a result of employing the three-stage tightening
operation, the clamping structure becomes too long for a fuel hose
having low pressure-resistance, and layout of such clamping
structure is difficult.
[0003] By the way, in the case where a clamping structure is used
for connecting an automatic transmission with a radiator as is the
case of the clamping structure for connecting an oil hose with a
metal pipe in an automobile, oil having high temperature and high
pressure flows through the clamping structure. For this reason, the
hose clamping structure is required to have pressure-resistance of
25 kgf/cm.sup.2 or higher at high temperature, which is higher than
the pressure-resistance of the hose clamping structure for the fuel
hose. Further, in such a hose clamping structure, it is required
that a portion tightened with a sleeve member has a length as small
as possible due to the relationship with a location where the hose
clamping structure is provided, and in addition, is required to be
low in price. Considerations have been made as to what design of
hose clamping structure is suitable for such an application. For
example, in the above case of the hose clamping structure for a
fuel hose, it is necessary to use an adhesive agent or a coating
agent. This results in increasing the price of the connection
structure. In addition, flat tightening operation cannot attain
sufficient pressure-resistance and there is a possibility that a
rubber hose may come off.
[0004] Contrary to the above, as shown in FIG. 3, it is possible to
tighten the sleeve member in a two-stage tightening operation
instead of flat tightening operation, without using an adhesive
agent. The two-stage tightening operation is conducted by pressing
a sleeve member 1 from eight directions on the circumference toward
an axial center by use of a tightening dice 4 normally divided into
eight segments in its circumferential direction and having
projections 4a at opposite ends radially inwardly projected into a
rectangular shape in cross section. However, in this hose clamping
structure, a rubber hose 3 is clamped only at two ring-shaped
tightening sections 2 of the sleeve member 1 in an axial direction.
In this structure, the tightening force of the sleeve member 1 is
not sufficient, and the hose clamping structure does not exhibit
sufficient pressure-resistance at high temperature.
[0005] Further, in the hose clamping structure for a power steering
hose, a rubber hose is insertedly fitted to a metal pipe, and a
sleeve member is provided to cover the rubber hose. Then, the
sleeve member is tightened in a three-stage tightening operation at
positions corresponding to the ring-shaped grooves of the metal
pipe. In this structure, it is possible to attain sufficiently high
tightening strength without using an adhesive agent. If, however, a
hose is long and has a curved portion, a large-sized pipe rolling
apparatus is used. In this case, the production cost is increased,
thereby increasing the price of the hose clamping structure.
Further, since this hose clamping structure needs a three-stage
tightening operation, the tightening portion becomes long.
Accordingly, the hose clamping structure also becomes long, and
there is a possibility that the layout thereof is limited when it
is arranged.
SUMMARY OF THE INVENTION
[0006] The present invention has been made to solve the
above-described problem, and an objective thereof is to provide a
hose clamping structure simple in design and low in price, capable
of exhibiting pressure-resistance high enough to withstand a
passage of fluid with high temperature and high pressure even if no
adhesive agent is used and the portion tightened with the sleeve
member is short in length.
[0007] In order to achieve the above-described objective, the
present invention provides a hose clamping structure including: a
metal pipe having an inserting end portion straightly extending in
an axial direction at one end and having a ring-shaped projecting
portion at a leading end of the inserting end portion; a rubber
hose insertedly fitted to the entire outer surface of the inserting
end portion of the metal pipe by press-fitting and secured thereto
in an unbonded manner; and a metallic tubular sleeve member mounted
to the outer surface of the rubber hose and extending over the
substantially full length of the inserting end portion, and
tightened from outside toward an axial center direction along a
circumferential direction so as to clamp the rubber hose to the
metal pipe. The sleeve member is tightened in a two-stage
tightening operation where the sleeve member is tightened at two
portions apart from each other in an axial direction, and a first
tightening portion at the leading end side of the inserting end
portion is longer in length than a second tightening portion
inwardly located in an axial direction, and the first tightening
portion extends to reach the leading end of the inserting end
portion.
[0008] In the present invention, the sleeve member mounted to the
outer surface of the rubber hose insertedly fitted to the metal
pipe and extending over the entire length of the inserting end
portion of the metal pipe is tightened in a two-stage tightening
operation where the sleeve member is tightened at two portions
apart from each other in an axial direction. The first tightening
portion at the leading end side of the inserting end portion has an
axial length larger than the second tightening portion inwardly
located in an axial direction. At the same time, the first
tightening portion extends to reach the leading end of the
inserting end portion. With this arrangement, the tightening force
of the first tightening portion is exerted to the leading end side
of the rubber hose, and the tightening force for clamping the
rubber hose to the metal pipe is increased as compared with a
conventional two-stage tightening operation. As a result, high
pressure-resistance can be assured in a hose clamping structure
through which a fluid with high temperature and high pressure is
passed. That is, it is possible to prevent the hose from coming off
caused by an inner pressure at high temperature (at about
150.degree. C.) which is assumed in an actual use. In addition,
since the sleeve member is tightened in a two-stage tightening
operation, the length of the portion to be tightened with the
sleeve member can be reduced and the space occupied by the hose
clamping structure can be reduced accordingly. Further, it is
enough to merely form a ring-shaped projecting portion at the
leading end of the metal pipe, and such a ring-shaped projecting
portion can be formed by bulging process which is simpler as
compared with rolling process and is low in cost. In addition,
since an adhesive agent is not necessary, costs for an adhesive
agent and its coating process are unnecessary. As a result, the
cost for the hose connecting structure of the present invention is
reduced.
[0009] In addition, the first tightening portion may be formed by
an integral unit including a tubular portion substantially parallel
to an axial direction at an inner end side in an axial direction,
and a tapered portion tapered and widened into a conical shape from
the tubular portion toward the leading end. Since the first
tightening portion includes the tubular portion substantially
parallel with the axial direction at an inner end side in an axial
direction, and the tapered portion tapered and widened into a
conical shape from the tubular portion toward the leading end,
there is no fear that the tapered portion crushes the ring-shaped
projecting portion formed at the leading end of the metal pipe, and
the ring-shaped projecting portion can be properly tightened.
Accordingly, the tightening force at the first tightening portion
is increased, and as a result, the tightening force of the entire
sleeve member for clamping the rubber hose is increased.
[0010] Further, the tightening rate of the tapered portion when it
compresses the rubber hose between the tapered portion and the
ring-shaped projecting portion can be set to 30 to 40 percent.
Here, the tightening rate of the sleeve member is a difference in
thicknesses before and after the rubber hose is tightened, that is,
a rate obtained by dividing the thickness of the rubber hose after
the tightening operation by a thickness of a rubber hose before the
tightening operation. Since the tightening rate of the tapered
portion of the first tightening portion when it compresses the
rubber hose against the ring-shaped projecting portion is set to 30
to 40 percent, the tapered portion exhibits proper tightening
effect, and the tightening force of the entire sleeve member is
increased in conjunction with the tubular portion and the second
tightening portion. As a result, high pressure-resistance required
in a hose clamping structure through which a fluid with high
temperature and high pressure is passed can be sufficiently
attained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a cross-sectional view schematically showing an
upper half of a hose clamping structure according to an embodiment
of the present invention.
[0012] FIG. 2 is a cross-sectional view of an upper half of the
hose clamping structure of FIG. 1 for schematically illustrating
the steps of tightening a sleeve member of the hose clamping
structure.
[0013] FIG. 3 is a cross-sectional view of an upper half of a
conventional hose clamping structure for schematically illustrating
the steps of tightening a sleeve member of the hose clamping
structure in a two-step tightening operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0014] Hereinafter, an embodiment of the present invention will be
described by way of drawings. FIG. 1 is a cross-sectional view
schematically showing an upper half of a hose clamping structure 10
according to this embodiment, for use in connecting a metal pipe
with an oil hose which connects an automatic transmission with a
radiator in an automobile. The hose clamping structure 10 includes;
a metal pipe 11 which is formed with an inserting end portion 12
extending straightly in an axial direction at one end, a
ring-shaped projecting portion 13 formed at the leading end of the
inserting end portion 12, and positioning projections 14a, 14b at
an inner end in an axial direction: a rubber hose 16 which is
insertedly fitted over the entire outer surface of the inserting
end portion 12 by press-fitting and is secured thereto in an
unbonded manner; and a tubular sleeve member 21 which is mounted to
an outer surface of the rubber hose 16 so as to extend
substantially over the entire length of the inserting end portion
12 and is tightened into a ring shape from the outer surface toward
an axial center direction and along the circumferential direction
so as to clamp and secure the rubber hose 16 to the metal pipe
11.
[0015] The metal pipe 11 is made of a thin steel pipe and the like.
The leading end of the straight-shaped inserting end portion 12
formed at one end of the metal pipe 11 is a ring-shaped projecting
portion 13 which projects into a ring shape. In addition, a pair of
inward and outward ring-shaped positioning projections 14a, 14b are
located at inner end positions of the inserting end portions 12 in
an axial direction so as to be slightly apart from each other in an
axial direction. The positioning projection 14a located at inner
side in the axial direction has an outer diameter slightly larger
than that of the positioning projection 14b located at an outer
side in the axial direction. The ring-shaped projecting portion 13
and the positioning projections 14a, 14b are produced by a simple
beading process at cost lower than the case of employing a rolling
process.
[0016] The rubber hose 16 is a high pressure-resistive hose, and
has an inner layer 16a, an outer layer 16b, and a reinforcing layer
16c provided at an boundary therebetween and made of knitting yarn
of vinylon or polyester. The inner layer 16a is made of oil
resistive rubber. The outer layer 16b is made of weather resistive
rubber. A sleeve member 21 is mounted to an outer surface of the
rubber hose 16 at its portion to be insertedly fitted to the metal
pipe 11.
[0017] The sleeve member 21 includes: a tube portion 22 having the
substantially same length as of the inserting end portion 12 of the
metal pipe 11 made of thin steel pipe; and a brim-shaped engaging
end portion 23 projecting from the inner end of the tube portion 22
in the axial center direction. The tube portion 22 is formed with a
second tightening portion 27 and a first tightening portion 24
separated from each other at two positions in an axial direction,
that is, at the side of the engaging end portion 23 and at the
opposite side thereto. The second tightening portion 27 is formed
into a ring shape slightly extending in parallel to an axial
direction. The first tightening portion 24 is constituted by: a
tubular portion 25 having the substantially same length as of the
second tightening portion 27 which is located at the side of the
second tightening portion 27 and is parallel to an axial direction;
and a tapered portion 26 which is continuous from the tubular
portion 25 and is tapered and widened into a conical shape toward
the leading end.
[0018] The inner surface of the engaging end portion 23 has a step,
and includes: an engaging projecting portion 23a at the inner end
side having an inner diameter slightly larger than the outer
diameter of the metal pipe 11; and an inner portion 23b having an
inner diameter slightly larger than the outer diameter of the
positioning projection 14b and continuous from the engaging
projecting portion 23a. When the sleeve member 21 is inserted into
the metal pipe 11, the engaging projecting portion 23a is brought
into contact with the positioning projection 14a. By being
tightened in this state, the engaging end portion 23 is insertedly
fitted and secured between the positioning projections 14a, 14b. If
necessary, the sleeve member may be made of a metal pipe other than
a steel pipe.
[0019] Next, a production of the above-mentioned hose clamping
structure will be described.
[0020] First, the sleeve member 21 in a straight tubular shape
before being tightened is fitted to the outer surface of the
inserting end portion 12 of the metal pipe 11 until the sleeve
member 21 is brought into contact with the positioning projection
14a of the metal pipe 11, and the leading end is tightened with a
tightening dice (not shown) and the like. Next, the leading end
portion of the rubber hose 16 is insertedly fitted to the metal
pipe 11 until it is brought into contact with the positioning
projection 14b of the metal pipe 11. Next, as shown in FIG. 2, the
sleeve member 21 is tightened in a two-stage tightening operation
where it is tightened by a tightening dice 31 from eight directions
at its outer surface.
[0021] The tightening dice 31 includes: a second projecting portion
32 at one end in an axial direction, that is, at the side of the
positioning projections 14a, 14b of the metal pipe 11 and having a
narrow width; a first projecting portion 33 at the other end in an
axial direction, that is, at the side of the ring-shaped projecting
portion 13, and having a wide width; and a groove 34 provided
between the second projecting portion 32 and the first projecting
portion 33 so as to separate them from each other and having a
width larger than the second projecting portion 32. The second
projecting portion 32 has an inner surface parallel to an axial
direction. The first projecting portion 33 includes: a tubular
portion 33a having the same width as of the second projecting
portion 32 at the side of the groove 34 and being parallel with an
axial direction; and a tapered portion 33b continuous from the
tubular portion 33a and widened into a conical shape and slightly
tapered toward the leading end. The length in an axial direction of
the tapered portion 33b is larger than that of the groove 34.
[0022] By being tightened at two stages from eight directions using
the tightening dice 31, the sleeve member 21 is pressed from its
outer surface toward an axial center direction, so that the first
tightening portion 24 and the second tightening portion 27 are
formed. As a result, the sleeve member 21 strongly clamps the
rubber hose 16 to the metal pipe 11. In this embodiment, the sleeve
member 21 is pressed from eight directions on the circumference
toward an axial center. Alternatively, it may be tightened in six
directions and the like in accordance with necessity such as an
outer diameter of the sleeve member and the like. In this
embodiment, when the sleeve 21 is tightened, the first tightening
portion 24 has an axial length longer than that of the second
tightening portion 27 inwardly located in an axial direction, and
the sleeve member 21 is tightened adequately without crushing the
ring-shaped projection portion 13 at the leading end of the metal
pipe 11 by the tapered portion 26 of the first tightening portion
24. Due to this arrangement, the tapered portion 26 assures proper
tightening in conjunction with the tubular portion 25 of the first
tightening portion 24, thereby enhancing the tightening force of
the sleeve member 21 as a whole.
[0023] The tightening rate of the tapered portion 26 when it
compresses the rubber hose 16 against the ring-shaped projecting
portion 13 (a portion C shown in FIG. 1) is in a range between 30
to 40 percent. At this tightening rate, the tapered portion 26
exhibits proper clamping effect. The tightening rate of the tubular
portion 25 and the second tightening portion 27 (portions A, B
shown in FIG. 1) is in a range between 30 to 40 percent. As a
result, in this embodiment, the tightening force of the sleeve
member 21 is improved as compared with conventional cases.
Therefore, it is possible to ensure high pressure-resistance of 25
kgf/cm.sup.2 or higher in the hose clamping structure 10 against a
passage of a fluid having high temperature and high pressure, that
is, it is possible to prevent the hose from coming off by an inner
pressure at high temperature.
[0024] In addition, the ring-shaped engaging end portion 23 of the
sleeve member 21 is insertedly fitted and secured between a pair of
positioning projections 14a, 14b located at an inner end in an
axial direction of the inserting end portion 12 of the metal pipe
11. Due to this arrangement, the sleeve member 21 is positioned to
the metal pipe 11 at the time of insertion, and it is possible to
ensure the prevention of the sleeve member 21 and the rubber hose
16 from coming off the metal pipe 11.
[0025] As described above, in this embodiment, since the sleeve
member 21 is tightened in two-stage tightening operation, the
tightening force of the first tightening portion 24 is enhanced.
Therefore, the high pressure-resistance of the hose clamping
structure 10 against a passage of a fluid having high temperature
and high pressure is ensured. Further, since the sleeve member 21
is tightened in two-stage tightening operation, it is possible to
decrease the length in an axial direction of the sleeve member 21.
As a result, the space occupied by the hose clamping structure 10
can be reduced. Further, the ring-shaped projecting portion 13 and
the positioning projections 14a, 14b of the metal pipe 11 can be
produced in a simple bulging process. Therefore, it is possible to
provide the metal pipe 11 at low cost. In addition, since there is
no need of an adhesive agent, costs for an adhesive agent and its
coating process are not necessary. Thereby, the cost of the hose
clamping structure 10 can be further reduced.
[0026] In the above-described embodiment, two positioning
projections 14a, 14b are formed in the metal pipe 11.
Alternatively, only either one of them is possible. In addition,
the engaging end portion 23 of the sleeve member 21 may be omitted
if necessary. The hose clamping structure in the above-embodiment
has been shown only as an example, and various modifications may be
made without departing from the principle of the present
invention.
* * * * *